BCAST(3PVM) PVM Version 3.4 BCAST(3PVM)NAME
pvm_bcast - Broadcasts the data in the active message buffer to a group
of processes.
SYNOPSIS
C int info = pvm_bcast( char *group, int msgtag )
Fortran call pvmfbcast( group, msgtag, info )
PARAMETERS
group Character string group name of an existing group.
msgtag Integer message tag supplied by the user. msgtag should be >=
0. It allows the user's program to distinguish between differ‐
ent kinds of messages .
info integer status code returned by the routine. Values less
than zero indicate an error.
DESCRIPTION
The routine pvm_bcast broadcasts a message stored in the active send
buffer to all the members of group. In PVM 3.2 and later the broadcast
message is not sent back to the sender. Any PVM task can call
pvm_bcast(), it need not be a member of the group. The content of the
message can be distinguished by msgtag. If pvm_bcast is successful,
info will be 0. If some error occurs then info will be < 0.
pvm_bcast is asynchronous. Computation on the sending processor
resumes as soon as the message is safely on its way to the receiving
processors. This is in contrast to synchronous communication, during
which computation on the sending processor halts until a matching
receive is executed by all the receiving processors.
pvm_bcast first determines the tids of the group members by checking a
group data base. A multicast is performed to these tids. If the group
is changed during a broadcast the change will not be reflected in the
broadcast. Multicasting is not supported by most multiprocessor ven‐
dors. Typically their native calls only support broadcasting to all
the user's processes on a multiprocessor. Because of this omission,
pvm_bcast may not be an efficient communication method on some multi‐
processors.
EXAMPLES
C:
info = pvm_initsend( PvmDataRaw );
info = pvm_pkint( array, 10, 1 );
msgtag = 5 ;
info = pvm_bcast( "worker", msgtag );
Fortran:
CALL PVMFINITSEND( PVMDEFAULT )
CALL PVMFPKFLOAT( DATA, 100, 1, INFO )
CALL PVMFBCAST( 'worker', 5, INFO )
ERRORS
These error conditions can be returned by pvm_bcast
PvmSysErr
pvmd was not started or has crashed.
PvmBadParam
giving a negative msgtag.
PvmNoGroup
giving a non-existent group name.
SEE ALSOpvm_joingroup(3PVM)
30 August, 1993 BCAST(3PVM)
